Work around pesign bug with -u

For some reason right now -u has to be at the end of the command line.
This doesn't seem to be true if it's not POPT_ARG_INT, so... make it not
a POPT_ARG_INT.

Signed-off-by: Peter Jones <pjones@redhat.com>
Don't call finalize_signatures if we're calling close_output()

close_output() /calls/ finalize_signatures(), so there's no need
to call it beforehand.

Signed-off-by: Peter Jones <pjones@redhat.com>
Make removing signature #0 actually work when it's not the only one.

Valgrind really is god's gift to C programmers.

Signed-off-by: Peter Jones <pjones@redhat.com>